Genetics of lipid deposition in the Japanese quail.

The research presented here was designed to investigate the mode of inheritance of fat and lean tissue deposition, and the relationship between them and body weight in Japanese quail. Heterotic effects were found for weight, size, and number of adipocytes in the abdominal fat depots, weight of the sartorial fat depot and percentage carcass fat with means for the hybrids being lower than those for the parental lines. General inferences concerning the importance of nonadditive genetic variation for lean and body weight were precluded due to inconsistencies observed among mating combinations.

Food and water intake following injection of glucose into the lateral ventricle of the brain of broiler type chicks.

The effects of glucose and 2-deoxy-D-glucose (2-DG) on food intake and water consumption were investigated in broiler chicks. Artificial cerebrospinal fluid (aCSF) containing either glucose or the glucose antimetabolite 2-DG was injected into the lateral brain ventricles of fasted and satiated chicks. The satiated chicks received 10 microliters of CSF containing either 5 or 10% 2-DG, whereas those fasted for 24 hr received CSF with 10, 20, or 30% glucose (dextrose) in 10 microliters volumes.

Genetic analyses of gustation in the fowl.

Preferences towards quinine sulfate (QS) and dextrose (DEX) were tested in purelines and reciprocal crosses of two lines of chickens that had undergone 22 generations of selection for high and low juvenile body weight. Parental line-F1 comparisons provided evidence for non-additive genetic variation for hedonic sensitivity towards QS and DEX, though in opposite directions. Additive genetic variation appeared to influence the preference ratios for both stimuli at super-threshold concentrations.

Correlated responses of chickens to selection for production of antibodies to sheep erythrocytes.

A bidirectional selection experiment was conducted to measure 5-day antibody titers to sheep erythrocytes in White Leghorn chickens. There was an immediate response to selection with significant differences between lines for the selected trait found in the S1 and all subsequent generations. Comparisons of S6, S7 and S8 generation females revealed differences between lines in disease resistance and in certain reproductive traits such as age at first egg, percentage hen-day egg production, percentage fertility and duration of fertility.

Influences of sequences of environmental factors on the response of chickens to fasting and to Staphylococcus aureus infection.

Weight gain of chickens following fasting was influenced by interactions between habituation to persons (socialization), stress (drinking water withheld) early in the life of the bird, and sex. Fasting affected socialized birds less than unsocialized birds. Body weight changes following Staphylococcus aureus infection were influenced by interactions between sex, stress early in life, socialization, and fasting.

Jejunal glucose absorption in selected high and low weight lines of domestic fowl.

Intestinal glucose uptake was measured in normal and dwarf chickens from lines selected fro high and low body weight. Jejunal tissue rings were excised from 9-week-old chicks and incubated in a medium containing .002 M glucose.

Sedimentation characteristics of newly synthesized Epstein-Barr viral DNA in superinfected cells.

Replicating Epstein-Barr virus (EBV) DNA molecules isolated from superinfected Raji cells were shown to consist of 80S to 65S and 58S (mature) molecules Pulse-chase experiments showed that radioactive label of DNAS molecules with the larger sedimentation coefficients was partially chased into 58S labeled forms. Formation of large concatemers of viral DNA could not be detected at any time after superinfection. The continuous presence of the 65S viral DNA intermediate throughout the replicative cycle combined with the observed inhibition of EBV DNA synthesis by addition of nontoxic levels of ethidium bromide to the superinfected cell culture led us to propose that EBV replication proceeds via a relaxed circular DNA intermediate.

Long-term exposure of chickens to three levels of social stress.

Cockerels were kept in environments characterized by high (HSS), medium (MSS), or low (LSS) levels of social stress for 3 or 4 months. Chickens raised in an environment of low light intensity (LSS) gained more weight than did those raised under natural lighting. Ability of chickens to produce antibody in response to antigen was greatly reduced, 2(15.

Dwarfism in diverse genetic backgrounds. 4. Effects of dietary energy.

The interactions in the response of dwarf and normal genotypes to dietary energy were studied in lines of chickens divergently selected for high or low juvenile body weight. The genetic background of the dwarf genotype significantly affected body weights, egg production, and egg quality. The dietary energy levels used did not significantly affect these traits or the differences due to genetic background.

The relationship between the dwarfing gene and E. coli infection in two populations of chickens.

Resistance to an E. coli challenge was studied in the 6th, 7th, and 8th backcross generations after the introduction of the sex-linked recessive dwarf gene (dw) into two populations of White Plymouth Rock chickens that had undergone bidirectional selection for juvenile body weight. In the B6 and B8 generations, the dwarf genotype from the HW line had significantly higher mortality and/or heart lesions than the heterozygotes while the homozygous normal chickens were intermediate.

Fertility of chickens from lines divergently selected for mating frequency.

Fertility comparisons of males under natural and artificial mating situations were made among lines of chickens selected for high and low mating frequency and the randombred population from which the selected lines originated. Although highly significant differences existed among lines for the frequency of sexual behaviors, there were no significant differences in fertility among lines either when males were with females for extended periods of time or when hens were artificially inseminated. Significant differences were found between mating systems for days to peak and duration of fertility.

Agonistic behavior, the development of the social hierarchy and stress in genetically diverse flocks of chickens.

The agonistic behavior and development of the social hierarchy of juvenile pullets were studied in two lines of chickens which had been divergently selected for juvenile body weight and in which the dwarf gene (dw) was segregating. The lines differed significantly in both the frequency and intensity of agonistic encounters. Dwarf and normal genotypes differed in the frequency of encounters in both lines, whereas for the intensity of encounters, the difference was only in the high weight line.

Repeatabilities of feed and water consumption of growing chickens.

Daily feed and water consumptions were obtained within 7-day periods for dwarf and normal males from lines selected for high and low juvenile body weight from 21 to 90 days of age. No significant differences were found among populations for the repeatabilities, and three measurements per week were sufficient to obtain an accurate estimate of feed and water consumption of growing chickens.

The effects of exogenous steroidal hormones on the testes of quail from selected high and low mating lines.

Several steroid hormones were tested for their effects on the testes of lines of Japanese quail selected for high and low mating frequency. Estradiol benzoate and testosterone propionate caused a complete and partial regression of the testes, respectively, while dihydrotestosterone did not affect testicular weight. Spermatogenesis was adversely affected by both estradiol benzoate and testosterone propionate but not by dihydrotestosterone.

Antibody production and Escherichia coli resistance in socially stable flocks of dwarf and nondwarf chickens.

Dwarf and normal pullets from lines that had undergone selection for divergence in juvenile body weight were maintained in cages as socially stable flocks. Antibody titers were measured at 6 and 14 weeks of age and an Escherichia coli challenge was administered at 16 weeks of age. There was a significant line by dwarf genotype interaction with dwarfs having lower antibody titers than normal pullets in the low weight line and higher antibody titers in the high weight line.

Effects of early environmental stresses on chicken body weight, antibody response to RBC antigens, feed efficiency, and response to fasting.

Stress early in life (SEL) by either overheating or water deprivation altered the responses of 4-to-18-week-old chickens selectively bred for high (HA) or low (LA) antibody response to sheep RBC. When unstressed, HA birds weighed more than LA birds. Following SEL, LA birds weighed more than HA birds.

Production and persistence of antibodies in chickens to sheep erythrocytes. 2. Resistance to infectious diseases.

A line of chickens selected for ability to product high antibody titers to sheep red blood cells exhibited stronger antibody to Newcastle disease, was more resistant to Mycoplasma gallisepticum, Eimeria necatrix, a splenomeglia virus, and feather mites and less resistant to Escherichia coli and Staphylococcus aureus infection than a line selected for a lack of ability to produce antibody titers. A line of chickens selected for a nonpersistance of antibody titers to sheep red blood cells was relatively more susceptible to all infectious agents tested than a line selected for a persistence of atibody titers.

Cell-mediated immunity in Marek's disease virus-infected chickens genetically selected for high and low concentrations of plasma corticosterone.

Lines of chickens genetically selected for high (HPC)-and low-plasma corticosterone (LPC) titers were assessed for cell-mediated immunity during Marek's disease tumorigenesis. Lymphocyte transformation (using phytohemagglutinin and 2,4-dinitrofluorobenzene-bovine serum complex) and mitogen-induced cellular cytotoxicity were evaluated with peripheral blood leukocytes. Chickens from the LPC line showed a greater lymphocyte transformation response than those from the HPC line.